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From: jdg@hpqtdla.sqf.hp.com (James Gentles)
Newsgroups: comp.sys.handhelds
Subject: Re: More about HP-28S
Message-ID: <1270027@hpqtdla.sqf.hp.com>
Date: 8 Feb 91 16:38:16 GMT
References: <1991Feb6.073911.25628@agate.berkeley.edu>
Organization: HP, Queensferry Telecomms, Scotland
Lines: 58

In comp.sys.handhelds, c60c-3ia@web-4d.berkeley.edu writes:
    2) How on earth can one change the speed of a HP-28S?  We know its pros and
    cons; now we want to try it ourselves

To put you out of your misery:
From daemon%gmuvax2.gmu.edu@hplb.hpl.hp.com Tue Jan 16 17:02 GMT 1990

SPEED - SET SPEED OF CALCULATOR.
        THIS COMMAND WILL CHANGE THE SPEED OF THE 28S VERSION 2BB BY
        MODIFYING THE SPEED NYBBLE. SPEED ACCEPTS A VALUE FROM 0 TO 15,
        7 BEING THE SYSTEM DEFAULT. IF BATTERIES ARE LOW, DO NOT CRANK UP
        THE SPEED TOO HIGH. SPEED SUFFERS FROM THE ANOMALY THAT THE SYSTEM
        MAY SET ITSELF BACK TO ITS DEFAULT UNEXPECTEDLY. PRESSING THE 
        ON/ATTN KEY MAKES THE 28 REVERT BACK TO NORMAL SPEED. 15 IS ABOUT TWICE
        NORMAL SPEED, AND 0 IS ABOUT ONE-THIRD NORMAL SPEED. CHANGE SPEED DOES
        AFFECT BATTERY CONSUMPTION.

                    0 - 15  :

CHK[532]
<< 'SPEED' -> S N            ;S IS SPEED, N IS VAR NAME.
  << PATH RCWS               ;SAVE PATH AND WORDSIZE ON STACK.
     64 STWS                 ;SET WORDSIZE TO 64.
     S R->B #FH AND          ;GET LEAST SIGNIF. NYBBLE.
     #1000000000000H *       ;SHIFT LEFT INTO POSITION.
     #C600302331DFFBCH OR    ;PUT NYBBLE IN PLACE.
     { # E60D51FFF00F1H      ;THIS PROGRAM IS FORCED TO BE 1ST VARIABLE
       # C808461241131H } +  ; IN ROOT DIRECTORY.
     HOME N RCL              ;STORE ORIGINAL PROGRAM ON STACK.
     SWAP N PURGE N STO      ;STORE MACHINE CODE AS 1ST VAR.
     #DFFB7H SYSEVAL         ;EXECUTE CODE.
     N STO STWS CD           ;RESTORE CALCULATOR STATE.
  >>
>>


Warnings:
This program forces itself to be the first in the HOME directory. It must
be typed in EXACTLY as above, YOU HAVE BEEN WARNED.
There must be a 'better' version of this, however this one works.
Speed may revert back to 7 at the calculators whim.
Running at speeds above 7 may cause:
1. "Memory Lost" (especially with low batteries)
2. The battery low indicator to come on prematurely
   (I think the last two statements are a 'Strange Loop' :-)

---------------------------------------------------------------------
      I have no professional connection with Hewlett-Packard's 
    calculator operations other than as a user of their products.
---------------------------------------------------------------------
Opinions expressed are my own, and are not intended to be an official
              statement by Hewlett-Packard Company
---------------------------------------------------------------------
Name:         James Gentles   GM4WZP
Organization: Hewlett-Packard  Queensferry Telecomunications Division
Email:        jdg@hpqtdla.hpsqf.hp.com                         hp-sdd 
Address:      Station Road, South Queensferry, West Lothian, Scotland
---------------------------------------------------------------------